1. Field of the Invention
The present invention includes a drive unit that records and reproduces data in and from recording media, for example, in a computer system, a multimedia system, and a data communication system, and recording media in and from which data can be recorded and reproduced with the drive unit.
2. Description of the Prior Art
It is a general practice to distribute a variety of software and data using recording media such as optical disks, optical magnetic disks, magnetic disks, and IC cards. It also is a general practice for users to save data and the like in these recording media.
In these cases, usually, a disk drive that performs recording and reproduction operations on recording media such as optical disks and optical magnetic disks is connected to a host computer, and the disk drive writes and reads data to and from the disks under control of the host computer.
Recording media include the above described disk types and IC memory types and the like, which have characteristics, respectively.
For example, disk types have the advantage of being able to record relatively large volumes of data, whereas they are considerably slower than IC memories in recording/reproduction operation speed.
On the other hand, although IC memories have a smaller data recording capacity, the recording/reproduction operation speed is very high.
Since different types of media respectively have advantages and disadvantages as described above, users should select appropriate media and media drive units so as to meet their use modes.
However, practically, there are many cases where disk media and IC memory media should be used differently for different uses, in which case both a disk drive unit and an IC memory drive unit (IC card reader, etc.) must be provided. This raises the problem of providing users with increased equipment installation loads, to be more specific, purchase costs, installation spaces, and system connections changes.
In addition to widely used disk media such as a ROM disk used for reproduction only and a rewritable RAM disk, a partial ROM disk (hereinafter referred to as a P-ROM disk) with a part of a user area allocated as a ROM area and another part as a RAM (rewritable) area is also being developed. The P-ROM disk permits more diversified and prospective use modes than the ROM and RAM disks.
However, a P-ROM disk has a drawback in that the manufacturing yield is relatively bad, and this fact hampers the widespread use of the P-ROM disk and the promotion of diversified use modes thereof.